McDonald Observatory

Official account for McDonald Observatory, a research unit of The University of Texas at Austin, located in the Davis Mountains of West Texas.

[McDonald Observatory @mcdonaldobs]

📣 The Board of Directors for the @giantmagellan Telescope has elected @mcdonaldobs Director Taft Armandroff as its new chair!

Learn about this exciting leadership transition:
https://t.co/is0snI64o1

[Taft Armandroff (left), Walter Massey (center) and Brian Schmidt (right)]

[NASA Astronomy Picture of the Day @apod]

What if you could see the entire sky -- all at once -- for an entire year?

That, very nearly, is what is pictured here.

Every 15 seconds during 2025, an all-sky camera took an image of the sky over the Netherlands.

Central columns from these images were then aligned and combined to create the featured keogram, with January at the top, December at the bottom, and the middle of the night running vertically just left of center.

What do we see? Most obviously, the daytime sky is mostly blue, while the nighttime sky is mostly black.

The twelve light bands crossing the night sky are caused by the glow of the Moon.

The thinnest part of the black hourglass shape occurs during the summer solstice, like today, when days are the longest, while the thickest part occurs at the winter solstice.

Equinoxes can also be located in the keogram, for example the northern-spring equinox from one year ago is about three-quarters of the way up.

Image Credit & License: Cees Bassa (Netherlands Institute for Radio Astronomy)

[NOIRLab @NOIRLabAstro]

The #AAS248 summer session is coming to a close after an engaging and astronomy-filled week. Thank you to @aas_office, our US Extremely Large Telescope Program partners, and all meeting participants. 🔭✨ @giantmagellan @TMTHawaii @NOIRLabAstro

📸 NOIRLab/NSF/AURA

[Texas Astronomy @UTAstronomy]

The Hobby-Eberly Telescope Dark Energy Survey (HETDEX) first public data release is now available!

https://t.co/hlIO7Q5NpT

[Texas Astronomy @UTAstronomy]

Exciting new clues about the nature of Little Red Dots from a team of astronomers led by UT Austin astronomer Vasily Kokorev!

[NOIRLab Science @NOIRLabScience]

Want to learn more about the US-ELT Program? Visit our booth in the exhibit hall to talk to reps from @TMTHawaii, @GMTelescope and @NOIRLabAstro #AAS248 🔭

[AAS Press Office @AAS_Press]

W. M. Keck Observatory: Astronomers Discover Third Galaxy Without Dark Matter https://t.co/32tNPxo8Js

[McDonald Observatory @mcdonaldobs]

🔭 We've added more summer star parties to the calendar, there's an awesome StarDate sale, and so much more -- Check out SkyTips for June! ✨

https://t.co/u9Q0mFYuR3

[CosmicAI @CosmicAI_Inst]

CosmicAI Student Lightning talk! Andy Morgan is a Science Intern at NSF @NOIRLabAstro
Listen to the talk "Machine Learning for Spectroscopic Redshift Estimation"
https://t.co/mF3jEUgUur

@NSF @SimonsFdn

[DarkSkyAdobe @DarkSkies107]

Star parties at the @mcdonaldobs are a great setting to get familiar with the night sky under clear bortle class 2 skies.

@stardate

[Texas Science & Natural History Museum @TXSciNatHisMus]

Thanks to @KXAN_News @ericmhenrikson for featuring our newest exhibit, “Masters of the Night: The True Story of Bats,” now open on the fourth floor at Texas Science & Natural History Museum on the @UTAustin campus! https://t.co/Z61kSh9Xcz

[CosmicAI @CosmicAI_Inst]

The Oden Institute for Computational Engineering and Sciences teamed up with @mcdonaldobs StarDate Magazine for an up close look at how astronomy and AI are solving each other’s problems.
Author: Olivia Castillo
Edits by Joanne Foote & the StarDate team
https://t.co/Yy9r653h8Z

[StarDate @stardate]

New Yorkers will see some special sunsets this week, as the descending Sun lines up along the urban canyons of Manhattan, and we’ll have details!

Join us for Manhattanhenge and more, this week — on StarDate!
https://t.co/ytg5KTnCv7

[istockphoto via secretNYC dot com]

[McDonald Observatory @mcdonaldobs]

🎉 Happy Graduation Weekend, Longhorns! 🤘

Congratulations @TexasScience & @UTAstronomy graduates on an incredible '25 – '26 academic year!

🎓 Graduation Schedule:
https://t.co/WpJ3L4hdj1

[McDonald Observatory @mcdonaldobs]

A galaxies livestream, Telescopes 101 Workshops, and the @nytimes visited the @mcdonaldobs - Check out SkyTips for May!

https://t.co/KLdP7VZvUn

[Jim Nicar @JimNicar]

May 5, 1939: Happy 87th Birthday to @UTAustin's McDonald Observatory, which opened as the world's 2nd largest telescope. Initially, some advocated it be placed atop Austin's Mount Bonnell, but wiser heads set the observatory under less populated and darker West Texas skies.

[StarDate @stardate]

⚫ Black holes are some of the most astounding objects in the universe, and we’ll tell you about some especially impressive ones!

💫 Join us this week for black holes, plus a disappearing meteor shower and more — on StarDate!
https://t.co/jXpTntXcaJ

[McDonald Observatory @mcdonaldobs]

🎉 It's @mcdonaldobs' 87th Birthday!
Many of the world's foremost astronomers attended the dedication on May 5, 1939, including (among others) Walter Baade, Bart Bok, Edwin Hubble, Jan Oort, Cecilia Payne-Gaposchkin, Henry Norris Russel, Martin Schwarzschild, and R.J. Trumpler!✨

[NaturalSciences @ UT @TexasScience]

The @NSF has awarded Graduate Research Fellowships & honorable mentions to 43 Texas Science undergrads, grad students & recent alumni this spring. Kudos to all of these exceptional students!

#TexasScience #GraduateEducation #STEMEducation
https://t.co/OpAToNv1DW

[McDonald Observatory @mcdonaldobs]

This is not a cool album cover - Though it totally could be!

Created by @UTAustin astronomer Jed McKinney, this image depicts wavelengths associated with molecules present ten billion years ago - And they might help solve a riddle about our universe!
🔗 https://t.co/2JgLUyCk0u

[McDonald Observatory @mcdonaldobs]

✨ WOW!! ✨
Y'all's generosity has us stammering! 💖
🚀 We surpassed our fundraising goal - And in record time!
Thank you SO MUCH for supporting @stardate during @UTAustin's 40 Hours for the Forty Acres.
🤘We're proud to be part of the Longhorn nation & excited for the future!